EXPULSION OF THE AFGHANS 323 plunder of a Russian caravan by the Khan of Khiva and the losses sustained by Russian subjects at Shamakha. Mahmud, whose knowledge of foreign policy must have been slight, informed the Muscovite ambassadors that he could control neither the Uzbegs nor the Lesgians. The fact was self-evident, but the admission strengthened the case for a forward policy, and Peter felt justified in acting upon it. He descended the Volga in a flotilla carrying thirty-three thousand infantry and effected a junction in Daghestan with a force of cavalry which had marched from Astrakhan.1 He issued a proclamation in which he de- clared that he had no designs of territorial aggrandisement, after which he took possession of Derbent, the importance of which has already appeared in this history. The Tsar was proceeding towards Shamakha and Baku when an Ottoman ambassador appeared on the scene, announced the capture of Shamakha by a Turkish force, and declared that any further advance by Russia would be deemed a casus belli. Peter was unwilling to provoke hostilities with Turkey at this juncture and withdrew to Russia, leaving a garrison of three thousand men at Derbent. His Occupation of Resht and Baku> A.D. 1723.—During the following winter Resht was besieged by the invading Afghans. Its Governor sent an envoy to Astrakhan and offered to open the city gates to a Russian army. Peter at once took advantage of this piece of good fortune, and occupied not only Resht but other centres. The adminis- tration of the province, however, was not interfered with, but remained in the hands of the local Khans. During the summer that followed the occupation of Resht, Baku was bombarded and capitulated. The Treaty of Shah Tahmasp with Russia^ A.D. 1723.— Tahmasp, unable to meet the invaders in the field, made a bid for the support of Peter. In return for the expul- sion of the Afghans, to which Russia pledged herself, Tahmasp agreed to cede Shirwan, Daghestan3 Gilan, Mazanderan, and Astrabad. But no attempt was made by Peter to expel the Afghans, nor were any of the pro- 1 A good account of this expedition is given in the Memoir of P. H. JBrucfj a Scottish soldier of fortune who took part in the campaign.